A Ray of greenish energy springs from your finger toward a creature within range.

Make a ranged spell attack against the target. On a hit, it takes 3d8 poison damage and must make a Constitution saving throw. On a failed save, it falls unconscious for two rounds. At the start of each of its turns, the target takes 1d10 poison damage while it is unconscious. If the target takes any damage other than from this spell, it can repeat the saving throw. Ending the effect on a success. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the initial damage increases by 1d8 for each slot level above first. When you cast this spell using a spell slot of 6th level or higher, the initial damage increases by 1d8 and the repeating damage increases by 1d10 for each slot level above 6th.